Some semiconductor devices have multiple power domains that allow the device to perform with varying power consumption. For example, when operating in low-power mode, a device's power consumption may be reduced by disconnecting one or more circuits from a power supply using one or more power switches. In general, these power switches are large, and therefore their subthreshold or leakage currents—that flow when the power switches are turned off—are significant.
As the inventors hereof have recognized, leakage has become a major contributor to the overall power consumption of modern semiconductor devices, particularly for devices designed to operate with low-power. As such, a need has been identified for a low-power circuit that is able to control the threshold voltages of certain transistors and/or to drive the gate of a power switch beyond its normal supply voltage range in order to reduce the power consumption due to subthreshold currents.